Integration of waveguide-type wavelength demultiplexing photodetectors by selective intermixing of InGaAs/InGaAsP quantum well structure

Abstract

Using the selective intermixing of an InGaAs-In-GaAsP multiquantum-well (MQW) structure, a wavelength demultiplexing photodetector which can demultiplex two widely separated wavelengths was fabricated. An InGaAs-InGaAsP MQW with a u-InP cladding layer and a u-InGaAs cap layer, grown by metal organic chemical vapor deposition was used. Selective area intermixing of the InGaAs-InGaAsP MQW structure was done by a rapid thermal annealing after the deposition and patterning of the SiO 2 dielectric layer on the InGaAs cap layer. The integrated structure consists of shorter and longer wavelength sections, separated by an absorber section. Shorter wavelength and absorber sections were intermixed with the SiO 2 dielectric layer. At a wavelength of 1477 nm, the output photocurrent ratio was enhanced as the length of the absorber region increased and a ratio of over 30 dB was observed, while at a wavelength of 1561 nm, an output photocurrent ratio of 18.9 dB was observed. Index Terms-Dielectric cap annealing, dual wavelength photodetector, InGaAs-InGaAsP multiquantum wells, integrated optics, quantum-well intermixing, waveguide photodetector, wavelength demultiplexing. I. INTRODUCTION D UE TO the current development of fiber manufacturing technologies and rare earth-doped fiber amplifiers, wide wavelength ranges (band), which were difficult to utilize in the past, now hold great promise for future applications [1]-[2]. Thus, photodetectors (PDs) that can demultiplex wavelength bands have a great deal of potential relative to fiber-optic communication systems of the future. In achieving such devices that are monolithic, techniques for fabricating regions that have different bandgap energies on the same wafer are required. Several techniques exist for fabricating such regions selectively: selective area growth using SiO masks in conjunction with metal organic chemical vapor deposition (MOCVD) [3], laser-assisted metal organic molecular beam epitaxy (MOMBE) [4], the quantum-confined Stark effect (QCSE) in multiquantum-well (MQW) structures [5], and quantum-well intermixing techniques [6]. Among these, the

Theoretical analysis of diffused quantum-well lasers and optical amplifiers

“…However, they split in the short-wavelength region ( 1460 m), which is an important feature in a polarization-independent device. In order to understand this feature, we study in detail the OME, Fermi occupation factor, and joint density of state (JDOS), which are the three main factors of the material gain given by (6). In Fig.…”

“…INCE the first report of disordering of superlattice in 1981 [1], quantum-well (QW) intermixing has been intensely investigated not only for the realization of monolithic integrated optoelectronic circuit [2], but also for improving the performance of optical components such as lasers [3], amplifiers [4], modulators [5], and photodetectors [6]. This is because relatively simple and mature post-growth techniques such as rapid thermal annealing [2] and high-power laser photoabsorption [7] are involved in QW intermixing, which provide useful and controllable changes of optical properties and operation wavelength through the modification of the composition profile.…”

“…For instance, DFQWs have been introduced to form window structures at the facets of lasers [3] and photodetectors [6] based on blueshifting the bandgap energy. As a result, the catastrophic optical damage is diminished and the output power of the laser and the detected power of the photodetector significantly increase.…”